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Re: [Qemu-devel] [Qemu-block] [PATCH v5 1/4] Add new block driver interf
From: |
Wen Congyang |
Subject: |
Re: [Qemu-devel] [Qemu-block] [PATCH v5 1/4] Add new block driver interface to add/delete a BDS's child |
Date: |
Thu, 8 Oct 2015 10:06:48 +0800 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 |
On 10/08/2015 02:33 AM, Max Reitz wrote:
> On 22.09.2015 09:44, Wen Congyang wrote:
>> In some cases, we want to take a quorum child offline, and take
>> another child online.
>>
>> Signed-off-by: Wen Congyang <address@hidden>
>> Signed-off-by: zhanghailiang <address@hidden>
>> Signed-off-by: Gonglei <address@hidden>
>> Reviewed-by: Eric Blake <address@hidden>
>> ---
>> block.c | 50
>> +++++++++++++++++++++++++++++++++++++++++++++++
>> include/block/block.h | 5 +++++
>> include/block/block_int.h | 5 +++++
>> 3 files changed, 60 insertions(+)
>>
>> diff --git a/block.c b/block.c
>> index e815d73..1b25e43 100644
>> --- a/block.c
>> +++ b/block.c
>> @@ -4265,3 +4265,53 @@ BlockAcctStats *bdrv_get_stats(BlockDriverState *bs)
>> {
>> return &bs->stats;
>> }
>> +
>> +/*
>> + * Hot add/remove a BDS's child. So the user can take a child offline when
>> + * it is broken and take a new child online
>> + */
>> +void bdrv_add_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
>> + Error **errp)
>> +{
>> +
>> + if (!parent_bs->drv || !parent_bs->drv->bdrv_add_child) {
>> + error_setg(errp, "The BDS %s doesn't support adding a child",
>> + bdrv_get_device_or_node_name(parent_bs));
>> + return;
>> + }
>> +
>> + if (!QLIST_EMPTY(&child_bs->parents)) {
>> + error_setg(errp, "The BDS %s already has parent",
>> + child_bs->node_name);
>> + return;
>> + }
>> +
>> + parent_bs->drv->bdrv_add_child(parent_bs, child_bs, errp);
>> +}
>> +
>> +void bdrv_del_child(BlockDriverState *parent_bs, BlockDriverState *child_bs,
>> + Error **errp)
>> +{
>> + BdrvChild *child;
>> +
>> + if (!parent_bs->drv || !parent_bs->drv->bdrv_del_child) {
>> + error_setg(errp, "The BDS %s doesn't support removing a child",
>> + bdrv_get_device_or_node_name(parent_bs));
>> + return;
>> + }
>> +
>> + QLIST_FOREACH(child, &parent_bs->children, next) {
>> + if (child->bs == child_bs) {
>> + break;
>> + }
>> + }
>> +
>> + if (!child) {
>> + error_setg(errp, "BDS %s is not a child of %s",
>> + bdrv_get_device_or_node_name(child_bs),
>> + bdrv_get_device_or_node_name(parent_bs));
>> + return;
>> + }
>> +
>> + parent_bs->drv->bdrv_del_child(parent_bs, child_bs, errp);
>
> How about we make this (BlockDriver.bdrv_del_child()) take a BdrvChild
> instead of a BDS? We could even make bdrv_del_child() as a whole take a
> BdrvChild parameter, but I don't suppose that would help much.
bdrv_add_child() takes a BDS, so I use BDS here.
Thanks
Wen Congyang
>
> Max
>
>> +}
>> diff --git a/include/block/block.h b/include/block/block.h
>> index ef67353..665c56f 100644
>> --- a/include/block/block.h
>> +++ b/include/block/block.h
>> @@ -616,4 +616,9 @@ void bdrv_flush_io_queue(BlockDriverState *bs);
>>
>> BlockAcctStats *bdrv_get_stats(BlockDriverState *bs);
>>
>> +void bdrv_add_child(BlockDriverState *parent, BlockDriverState *child,
>> + Error **errp);
>> +void bdrv_del_child(BlockDriverState *parent, BlockDriverState *child,
>> + Error **errp);
>> +
>> #endif
>> diff --git a/include/block/block_int.h b/include/block/block_int.h
>> index 2f2c47b..64cbc55 100644
>> --- a/include/block/block_int.h
>> +++ b/include/block/block_int.h
>> @@ -288,6 +288,11 @@ struct BlockDriver {
>> */
>> int (*bdrv_probe_geometry)(BlockDriverState *bs, HDGeometry *geo);
>>
>> + void (*bdrv_add_child)(BlockDriverState *parent, BlockDriverState
>> *child,
>> + Error **errp);
>> + void (*bdrv_del_child)(BlockDriverState *parent, BlockDriverState
>> *child,
>> + Error **errp);
>> +
>> QLIST_ENTRY(BlockDriver) list;
>> };
>>
>>
>
>